1. Field of the Invention
The present invention relates to a print element substrate, a method of manufacturing the same, a printhead, and a printing apparatus.
2. Description of the Related Art
An arrangement example of a print element substrate I0 will be described with reference to FIG. 6. The print element substrate I0 includes a printing portion 10, power wiring patterns 100 (100a and 100b) for supplying a power supply voltage to the printing portion 10, an insulating protective film 320 covering the printing portion 10 and power wiring patterns 100, and a cavitation-resistant film 110. In addition, an orifice plate PL forming a nozzle NZ for discharging ink and an ink channel ICH for supplying ink can be arranged on the print element substrate I0.
A region Ra indicates a region where the ink channel ICH for supplying ink to the printing portion 10 is formed. A region Rb indicates a region which the ink in the ink channel ICH does not contact (for example, an electrode region where a bonding pad and the like are formed).
The cavitation-resistant film 110 is made of a conductive material having a high cavitation resistance such as tantalum (Ta). Thus, the cavitation-resistant film 110 protects the printing portion 10 and power wiring pattern 100a from cavitation caused by ink. The cavitation-resistant film 110 is formed in the region Ra by forming a conductive member such as Ta on the protective film 320, and etching a portion of the conductive member, which covers the region Rb.
When performing the above-described etching, a residue 110x of the conductive member may form in a step portion of the protective film 320 covering the power wiring pattern 100b. This residue may decrease the reliability of the print element substrate I0, for example, may shortcircuit the wiring patterns. On the other hand, it is also possible to perform overetching so as not to form the residue 110x. However, this may damage the protective film, and may also damage the printing portion or wiring patterns.
In particular, it is necessary to decrease the spacings between the wiring patterns in order to reduce the chip area of the print element substrate. If the wiring pattern spacings are decreased, however, the above-described residue readily forms.